Ice detector means



July 12, 1949. w. B. POND' ICE DETECTOR MEANS 2 Sheets-Sheet 1 Filed Aug. 11 1945 INVENTOR.

July12,1949. WB OND 2,476,217

ICE DETECTOR MEANS Filed Aug. 11. 194:5 2 Shetets-Sheet 21 INVENTOR.

BY B.Po1zd 'A/LMXQW,

Patented July 12, 1949 UNITED SITES OFFICE ICE DETECTOR MEANS Application August 11, 1943, Serial No. 498,247

2 Claims. (Cl. 244134) My present invention relates to control devices and more particularly to light conducting means responsive to icing conditions prevailing on an exposed aircraft surface for operating inflatable ice eliminating units for aircraft or suitable indicator means.

It has been observed that such units or boots give better ice removal if approximately an eighth of an inch of ice is allowed to accumulate before the boots are inflated. This is because the ice must build to a definite thickness in order to develop enough tensile strength to overcome adhesion. If the inflatable ice eliminating boots are operated with insuff cient ice accumulated on them, the stretch of the rubber cracks the thin layer of ice, breaking it into many very small pieces, some of which are dislodged, but most of which remain. Further accumulation of ice builds on the little particles which remain and thus develops a flexible ice which is really composed of a number of separate little islands. Once such a condition has been established, additional cycles of inflation and deflation are relatively ineffective because further ice formation tends to accumulate only on the remaining particles and the stretch of the rubber naturally localizes in the areas between the islands without disturbing them. However, if the ice be permitted to accumulate to a greater thickness, it becomes increasingly more difficult to apply sulficient pressure through the boots to effect the cracking of the ice to facilitate its removal.

It is therefore of extreme importance that the operator of the plane be so advised or that the inflatable ice eliminating boots be operated when the ice has accumulated to the optimum thickness for its removal.

An object of my invention therefore is to provide control means responsive upon such predetermined optimum icing conditions prevailing on an aircraft surface to operate suitable ice eliminating means for removing the accumulated ice from such surface, whereby said control means is simultaneously conditioned for reoperation upon a recurrence of such optimum predetermined condition.

Another object of my invention is to provide electronic control means directly responsive to the thickness of an ice accumulation for performing a control function.

Another object of my invention is to provide novel light conducting means responsive to ice thickness for performing a control function.

Another object of my invention is to provide means mounted directly upon a boot responsive to an ice accumulation thereon for initiating the operation of the boot.

Another object of my invention is to provide novel light conducting means mounted directly upon a boot and so arranged that the light conducted thereby may be interrupted by the formation of a predetermined thickness of ice upon the boot so as to initiate the operation of the boot for removing the same.

Another object of by invention is to provide control means responsivev to ice thickness and means for removing the ice from the control means operated by the said ice thickness responsive means.

Another object of my invention is to provide a novel light responsive means and means for conducting light to said light responsive means from a fixed source of light, so arranged that upon the formation of a predetermined thickness of ice upon a boot the said conduction of light rays to said light responsive means will be interrupted by said ice formation for causing said light responsive means to perform a control function.

A further object of my invention is to provide a compact control device responsive to ice thickness of great efiiciency in comparison to its size and of such simplicity in construction as to adapt it for manufacture and installation at low cost.

Other objects and advantages of this invention are set forth in the following description, taken with the accompanying drawings; and the novel features thereof are pointed out in the appended claims.

cially in matters of shape, size and arrangement of parts within the principle of the invention to the full extent indicated by the broad and general meanings of the terms in which the appended claims are expressed.

In the accompanying drawings which form a part of this specification like characters of reference indicate like parts in the several views wherein:

Figure 1 is a view of a portion of the forward The disclosure, however, is illustrative a only and we may make changes in detail, espeedge of a wing of a plane illustrating the application of one form of my control device.

Figure 2 is an end view of Figure 1.

Figure 3 is a cross sectional view of Figure 1 taken along the lines 3-3 and looking in the direction of the arrows.

Figure 4 is a cross sectional view similar to Figure 3 showing the boot in an inflated position.

Figure 5 is a diagrammatic view illustrating a form of control circuit which may be utilized with m control device.

In the form of my invention illustrated in Figures l throughad thereis indicated by numeral? In an airpla-ne'wing provided with an inflatable ice eliminating boot ll formed of resilient rubberlike material and positioned along the leading' edge of the wing Ill.

The boot I I may be of the type shown for example in the co-pending applicationof Donald M. Lawrence, David Gregg, and Myron L; Taylor; Serial No. 498,248 dated August 11, 194% and owned by the assignee of therpresent application and has provided inflatable tubes l3, I4, and IS.

The tubes |3, l4, and I5. are expanded and contractedl in-.a recurring; GYClBrOfi operation.- at. intervals which: may: be; determined; by; a timing; ar.- rangement suchas: shown inthe co-pending; ap plication of Myron. L, Taylor, WilliamB-e Bond, and. Herbert A Eayrs,-. Serial No: 498,250 dated: August. 11,. 1943; now matured. into- Patent. No 2,444,208, issued June 29, 1948-.

The leading edge of the- Wing- I is" suitably apenturedi at t6 and I1 andhas disposech therein theinwardly projecting. cushionmembersl8 and.

| formedintegralrwiththe boot..|'|..

Projectin lthrough. therboot and. thecushion membersv I8 and. I3 arelight conducting rods 20.. and 21'. The rod 20 has. provided. longitudinal ends 22 and 23 while. the rod 21 has formed similar longitudinal ends. 24 and. 25'. The. rods 20 andil are formediofa. suitable light conducting material, such asglass, quartz, or light conducting plastic material such as l'ucitehaving as iswell known in. the art its outer surfaces with the exception ofthe longitudinal ends thereof so treated or so coatedwith a suitable material as to. prevent light rays from emerging from the sides of the rods 2 0' and 21;

The rods 20 and 2| are thus so arranged thatlight rays entering one' of the longitudinal ends thereof will be conducted by internal reflection through the said rod andout" the opposite longitudinal endthereof.

The'rod's 2 0 and 21 are curved and so posit ioned that, upon the tube I 4 beingdeflated as shown Figure 3 the longitudinal end 23- of' rod will: be disposed opposite and in spaced relation to: the longitudinal end 24 of the' rod- 2|;

Screw thread'edly engaged at the longitudinal end 22 of. the rod: 2:0 is: a plastic: holder 26 formed of; nonelight conducting material inwhich is formed a channel 26A having mounted therein in: a suitable screw threaded-z socketv a minute: electric bulb" 2:1. The: electric bulb 2:1 has: pro:- vided. the: electrical conductors; 23 and: 23 whiclr,v asashcwn in Figure 5, are connected to the opposite terminals of asuitable source: of electrical energy 30.

The electric bulb 21 thus forms a. source of light rays which are directed into the longitudinalend 22 of. the light conducting rod; 2.0. The said light rays are conducted b means of inter-- nal reflection through the rod 20 and out. theopposite longitudinal end 23 There is similarly screw threadedly engaged at the longitudinal end 25 of the rod 2|, 2. plastic holder 30 formed of non light conducting material in which is formed a channel 30A having mounted therein in a suitable screw threaded socket a photoelectric cell 3| responsive to light rays directed out the longitudinal end 25 of the rod 2| into the channel 30A.

The rod 2| is arranged so that light rays directed into the longitudinal end 24 are conducted by internal reflection through the rod 2| and out the longitudinal end 25.

'Iihe outer exposed surfacesof theirodsa 20 and 21 are protected from the weather by -suitable covers 20A and 2|A, respectively formed of rubher or other suitable material which may be readily vulcanized to the boot I I.

The photoelectric cell 3| has provided as best shown in' Figure 53 an anode 32 and cathode 33 which are connected to a suitable control circuit.

Inthe control circuit illustrated in Figure 5, the anode 32. is. kept at a positive potential with respect to the cathode 33 by connectin the anode 32zby. means of an electrical conductor 34 to the positive terminal of a suitable source of electricalenergy-35.

The negativeterminal of the sour-cent electr i cal. energy 35 is. connected. bya. conductor 36 to: the? positive terminal. of another sourcerofl else-- trical; energy,- 31. whichrhas. the, negative terminal) thereof connected by a conductor 38 to aresishance. element 39:. The; resistanca element.. 39: is connected. at the opposite terminal-lily a conductor; an. to the cathode. 3,3.of the photoelectric cell 31.

There isfurther. provided: in the:co ntrol. circuit: an. electronic valve, 4|. The, electronic valve; 4.1- has. provided a cathode 42, ashield grid 43. con.-

trol grid 44, an. anode or plate, 45, anda heater or. filament 4.6..

The cathode. 42 is. connected. b an electrical. conductor 41 to the conductor. 3,111 and isthus cone nected to the negativeterminal of. the source 0t electrical energ 35. and the, positiv terminal of. thesourceof.electricalenergy 3]..

One terminal of the filamentv 46 is connected-to. the conductor 411' leading to. the negative terminal. of the source of electrical energy 35,, while. the opposite terminal of; the filament. 4.61 is, connected by a conductor 48 toa. resistance: element iii-which. is in turn. connected by an. electrical conductor 50 to the conductor 34 leading. to the! positive. terminal of the. source of electrical. energy 35.

Theshield' grid 43 is connected by. a. conductor 5| to one terminal of! aresistance 52. The optic-- site terminal of the. resistance 52. isconnected by a conductor 53 to. the conductor 34 leading tothe. positive terminal. of the source. of electrical energy 3.51.

The anode or. plate 45' is further connected. by an electrical conductor 54. to. one terminal. of an. electromagnetic. coil 55. The opposite, terminal of the coil 55 is connected by a. conductor 55. to. the conductor 34 leading. to. the positive. terminal of the source of electrical energy 3.5. The. elec-- tromagnetic coil 55 is. connected across a con.-

denser 57.. The opposite plates. of the condenser 51 are connected by; electrical conductors 5B. and 59 respectively to conductors. 54 and 56...

The control grid 44 is connected by a. con ductor 6.41 to. the electrical conductor 4|).v Opposite plates of a condenser 6| are connected by conductors 62 and 63 respectively to. the, control grid 44 and the cathode 4.2...

The electromagnet 55 is arran cdl to. actuate. switch arms 64 and 64A for, controlling switch,

contacts 65 and 65A respectively. The switch arms 64 and 64A are arranged to open the switch contacts 65 and 65A upon energization of the electromagnet 55 and are biased under spring tension so as to close the switch contacts 85 and 65A respectively upon the deenergization of the electromagnet 55.

An electrical conductor 66 connects the switch arm 64 preferably into a timer circuit of the type shown in the above mentioned Patent No. 2,444,- 208, and indicated generally in Figuire 5 by the numeral 61, while the contact 65 is also connected into the timer circuit by a conductor '58. As described in the latter application the switch arm 64 may be arranged for closing a circuit for initiating a cycle of operation. Similarly the switch arm 64A is arranged to control a circuit for operating a suitable indicator 61A such as a light, alarm or whistle.

In operation, the circuit shown in Figure 5 is so arranged that upon an uninterrupted passage of light from the source 2! across the space between the ends 23 and 24 of the rods 20 and 2! and thus through the light conducting rods 20 and 2| to the photoelectric cell 3! an electronic flow will be set up by the light rays striking the photoelectric cell 3! causing the negative bias efiective on the control grid 44 to be reduced. Such reduction in the potential of the control grid 44 will cause the electronic flow within the electronic valve 4! to the plate 45 to be increased sufliciently for causing the energization through the plate circuit of the electromagnet 55 for actuation of the switch arms 64 and 64A to an open relationship with the contacts 65 and 65A, respectively.

However, upon the passage of light across the space between the ends 23 and 24 of the rods 20 and 2! being obstructed as upon an accumulation of ice on the boot I! of sufiicient thickness to close the space between the said ends the reduction in the light conducted to the photocell 3| will cause a decrease in the electronic flow from the photocell 3! so as to cause the negative bias of the grid 44 to be increased. Upon such increase in the negative bias of the grid 44, the electronic flow within the electronic valve 4! to the plate 45 will be decreased sufliciently so that the energization of the electromagnet 55 will be insufficient to hold the switch arms 64 and 64A.

in an open relation to the contacts 65 and 65A, respectively, against the spring biasing force exerted by the switch arms 64 and 64A whereupon the switch contacts 65 and 65A, respectively, will be closed by switch arms 64 and 64A, under such spring biasing force.

The rods 20 and 2! are positioned in relation to the surface of the boot I! so that the passage of light will be obstructed by a formation of ice of the predetermined optimum ice thickness desired.

Thus upon the accumulation or formation of the predetermined ice thickness, the switch arm 64 will close the contact 65 so as to cause the initiation of a cycle of operation such as explained in the above mentioned Patent No. 2,444,208, whereupon the tube !4 will be inflated as shown in Figure 4 causing the expansion of the boot and the pivotal movement of the light conducting rods 20 and 2! freely mounted in the boot I! as shown. The boot I! will then be deflated after a time interval determined by the timer 6'! as explained in the latter co-pending application.

Such inflation and deflation of the boot I! as will be readily apparent will cause the cracking of the ice formed thereon which will in turn be carried away by the airflow.

The tubes 3 and !5 will likewise be inflated and deflated as well as the remaining boots of the plane as explained in the aforenoted copending applications until the cycle of operation is completed, whereupon operation of the inflatable boots will cease until initiated once again by the formation of an ice accumulation of sufficient thickness. to obstruct the passage of light across the space between the ends 23 and 24 of the light conducting rods 23 and 24.

While in the illustrations herein I have shown my control device as controlling a timer of a type disclosed in the U. S. Patent No. 2,444,208, it will be readily apparent that if desired, the same may control any suitable type of electronic control or may control an indicator and the inflatable ice eliminating system may be controlled manually by the pilot.

Furthermore, suitable light responsive cells such as for example, photo-voltaic cells, seleniumcells or infra red ray cells and suitable control circuits therefore may be readily substituted for the photoelectric cell and control circuit provided herein.

Moreover, while I have disclosed a specific circuit for use with my control device, it will be readily apparent that any suitable control circuit may be readily substituted therefor.

Thus, although only one embodiment of my invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. The combination, with an aerofoil surface and means for removing ice therefrom, of a source of light carried within said aerofoil surface, a light responsive means carried with said aerofoil surface, means controlled by said light responsive means for operating said ice removing means, and internal reflecting rod means for conducting light from said source to said light responsive means, said light conducting means extending from said source of light and said light responsive means to the exterior of said aerofoil surface and arranged in relation to said aerofoil surface in such a manner that upon the accumulation of a predetermined thickness of ice on said aerofoil surface the conduction of light from said source to said light responsive means will be interrupted for causing operation of said ice removing means by said operating means.

2. In combination with an airplane, a mechanism including an expansible member secured to the airplane structure for removing an accumulation of ice from said structure, and means for operating said expansible member, of a pair of light conducting rods mounted on the outer surface of said expansible member, and said light conducting rods extending through said expansible member and having inner ends thereof positioned within said airplane structure and outer ends thereof positioned in spaced relation to each other on the outer surface of said expansible member, a source of light fastened at said inner end of one of said light conducting rods, a light responsive means fastened at said inner end of the other of said light conducting rods, said light conducting rods arranged for conducting light B. "POND.

=REFER1ENGES CITED The following references "are of recordin'fihe file of this patent:

Number UNITED PATENTS Name Date Horni Mar. 3, "1931 Hirs'ch1 1 Apr. 30,1935 "Bell Julyfi, 1938 Tyler May 23, 1939 Baer 1H July 11, 1939 Langley Aug, 29, 1939 may 1 Dec. 5, 1939 Baxter Feb. 11, 1941 'Siedle Sept. 29, 1942 Lichtgar'n "Sept. 16,1944 Peter-set a1 Oct. 10, 1944 McG'oltlrick Apr. 10, 1945 

